Research is proposed in the following areas: 1. The interaction of anti-cancer drugs with tubulin and their effects on the modes of tubulin self-assembly will be examined in detail, with particular attention on possible conformational and entropic effects. 2. The effect of solution variables, ligands and non-tubulin proteins on microtubule assembly will be examined by equilibrium thermodynamic and kinetic techniques. 3. The specific and non-specific interactions of solvent components with tubulin and other proteins will be investigated with particular attention on the manner in which they are involved in the isolation of tubulin by the cycle procedure.